Telecommunication service providers continually try to create new markets and to expand existing markets for telecommunication services and equipment. One important way to accomplish this is to improve the performance of existing network equipment while making the equipment cheaper and more reliable. Doing this allows the service providers to reduce infrastructure and operating costs while maintaining or even increasing the capacity of their wireless networks. At the same time, the service providers are attempting to improve the quality of telecommunication services and increase the quantity of services available to the end-user.
A conventional switching center typically contains a large switching fabric controlled by a main processing unit (MPU) that contains a large number of data processors and associated memories, often in the form of ASIC chips. Each of these MPU processors contains a call process client application for controlling the flow of control signals of a single call. Each call process client application in turn communicates with a call process server application that controls the flow of control signals for a large number of calls.
Thus, when a particular event occurs during a phone call (e.g., the call set-up, the invocation of three-way calling, call disconnection, or the like), control signals associated with the event are relayed from the origination station to the call process client application in the switching center. This call processing client application then relays the control signals to the call process server application, which actually performs the call processing service requested by the control signals.
Unfortunately, in large capacity systems, bottlenecks may develop around the call process server applications. Each call process client application must communicate with a particular piece of server hardware that is executing the call process server application. Due to the random nature of the start and stop of phone calls, in large systems, some servers may be near capacity and develop bottlenecks, while other servers still have plenty of adequate bandwidth. Moreover, a system failure in a particular piece of server hardware results in the loss of all call processes being handled by a call process server application being executed on the failed server.
Moreover, upgrading the call process server applications in a conventional switching center without interrupting existing service is extremely complicated. In some prior art systems, performing a software upgrade requires fully redundant (duplex) hardware in the switching center. The redundant components are split into an active side and an inactive side. Complex control software is required to manage the split (by swapping active and inactive sides) and to manage the process of merging the two halves of the system back into a unitary system. The redundant hardware adds excessive cost to the prior art switching center and the complex control software is expensive to develop, susceptible to errors due to its complexity, and difficult to maintain.
Therefore, there is a need for improved telecommunication network equipment and services. In particular, there is a need for switching centers that may easily undergo on-line software upgrades. More particularly, there is a need for switching centers that may be upgraded on-line without requiring the use of redundant hardware and without requiring complex and expensive control software.